OVERALL: Project Summary/Abstract The ASSIST Center?Accelerator Strategies for States to Improve System Transformations Affecting Children, Youth and Families?builds on an infrastructure developed through a 15-year collaboration between New York University School of Medicine (The IDEAS Center) and the New York State Office of Mental Health, creating the only national children's policy dissemination and implementation (D&I) research laboratory in the country focused on improving the uptake of policy-relevant, evidence-based services for youth with serious mental health disorders (SMHD). ASSIST will develop tools to improve the uptake of child mental health (MH) research evidence by state policymakers, and test two practical accelerator strategies to improve D&I of evidence-based practices in state systems. Guided by Shortell's Levels of Change Framework and Leeman et al's ?beyond implementation strategies,? ASSIST's objectives and specific aims support the National Institute of Mental Health's (NIMH) Strategic Research Objectives 3.3 and 4.4. The specific aims of the Center are to: Aim 1. Advance policy-relevant effectiveness, dissemination, and implementation research across multiple levels of state systems (policymakers, agencies, providers, youth/families), including meaningful engagement of diverse Center stakeholders, to improve publicly-funded services for youth with SMHD and their families; Aim 2. Identify state policy dissemination targets and test a set of brief and practical accelerator strategies (diagnostic and engagement) to improve clinical practice and youth and family outcomes; Aim 3. Advance the development of early and mid-career investigators interested in state MH policy and services research through the Training Unit's comprehensive training opportunities, structured mentoring program, pilot research funding, and access to a rich set of state and national-level datasets and methodological support (via the Methods Core [MC]) to support their career development; Aim 4. Identify and develop rigorous, practical, and novel methods for state policy research for use by health plans, payors, and states via the MC's Project Design and Analysis Services Unit (PDASU) and Data Coordinating Unit (DCU); and Aim 5. Engage Center stakeholders and disseminate Center findings nationally, via the Communications and Stakeholder Engagement Unit (CSEU), which will focus on the engagement and integration of stakeholder input into research projects, and the national dissemination of Center-developed research products, via the Center's website, newsletter, policy briefs, webinars, social media channels, and via our National Advisory Board, whose broad national membership and reach can accelerate the rapid dissemination of information and create efficiencies of effort in communicating Center research. This Center integrates transdisciplinary implementation and MH services research expertise within a healthcare quality framework involving six research institutions, seven academic disciplines, two state systems, a national dissemination network, and leverages existing NIMH-funded T32 and D&I training programs.